Recently, personal digital assistants (PDA) or other hand-held devices that combines computer, communication and consumer electronics technologies are becoming very popular because of their advantageous features including ability to write notes, record names, addresses and phone numbers, and to develop an appointment calendar. In the example of FIG. 1A, a hand-held electronic device 100, such as PDA, is typically mounted on a cradle 110 connected to a desktop or notebook computer 150 through a cable 120. In this manner, the hand-held electronic device 100 can synchronize and backup data with the computer 150. In addition, the cradle 110 works with an AC adapter 170 to recharge the hand-held electronic device 100 if the hand-held device 100 is nearly out of charge. To type accurately and improve productivity, on the other hand, a conventional portable keyboard 130 is attached to the hand-held electronic device 100, as shown in FIG. 1B, for quickly entering large amounts of data.
A hand-held electronic device attracts users due to its pocket size which allows easy transport. However, because it is compact, it requires the user to carry along the cradle and the portable keyboard to perform key entry, synchronize data as well as charge the hand-held device in any occasion, hence reducing the convenience of the hand-held electronic device and discouraging consumers from buying it. Apart from the above inconvenience, the conventional portable keyboard for the hand-held electronic device can not fit directly onto a desktop or notebook computer. Hence, it is awkward for a user to prepare an extra keyboard for computer use even though a portable keyboard for the hand-held device may already be owned.
Accordingly, what is needed is an input apparatus for a hand-held electronic device and a computer, unencumbered by the limitations associated with the prior art.